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| Titel |
A synthesis of cloud condensation nuclei counter (CCNC) measurements within the EUCAARI network |
| VerfasserIn |
M. Paramonov, V.-M. Kerminen, M. Gysel, P. P. Aalto, M. O. Andreae, E. Asmi, U. Baltensperger, A. Bougiatioti, D. Brus, G. P. Frank, N. Good, S. S. Gunthe, L. Hao, M. Irwin, A. Jaatinen, Z. Jurányi, S. M. King, A. Kortelainen, A. Kristensson, H. Lihavainen, M. Kulmala  , U. Lohmann, S. T. Martin, G. McFiggans, N. Mihalopoulos, A. Nenes, C. D. O'Dowd, J. Ovadnevaite, T. Petäjä, U. Pöschl, G. C. Roberts, D. Rose, B. Svenningsson, E. Swietlicki, E. Weingärtner, J. Whitehead, A. Wiedensohler, C. Wittbom, B. Sierau |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 15, no. 21 ; Nr. 15, no. 21 (2015-11-04), S.12211-12229 |
| Datensatznummer |
250120139
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| Publikation (Nr.) |
 copernicus.org/acp-15-12211-2015.pdf |
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| Zusammenfassung |
| Cloud condensation nuclei counter (CCNC) measurements performed at 14
locations around the world within the European Integrated project on Aerosol Cloud Climate and
Air Quality interactions (EUCAARI) framework have been analysed
and discussed with respect to the cloud condensation nuclei (CCN) activation
and hygroscopic properties of the atmospheric aerosol. The annual mean ratio
of activated cloud condensation nuclei (NCCN) to the total number
concentration of particles (NCN), known as the activated fraction A,
shows a similar functional dependence on supersaturation S at many
locations –
exceptions to this being certain marine locations, a free troposphere site
and background sites in south-west Germany and northern Finland. The use of
total number concentration of particles above 50 and 100 nm diameter when
calculating the activated fractions (A50 and A100, respectively)
renders a much more stable dependence of A on S; A50 and A100
also reveal the effect of the size distribution on CCN activation. With
respect to chemical composition, it was found that the hygroscopicity of
aerosol particles as a function of size differs among locations. The
hygroscopicity parameter κ decreased with an increasing size at a
continental site in south-west Germany and fluctuated without any particular
size dependence across the observed size range in the remote tropical North
Atlantic and rural central Hungary. At all other locations κ
increased with size. In fact, in Hyytiälä, Vavihill, Jungfraujoch
and Pallas the difference in hygroscopicity between Aitken and accumulation
mode aerosol was statistically significant at the 5 % significance level.
In a boreal environment the assumption of a size-independent κ can
lead to a potentially substantial overestimation of NCCN at S levels
above 0.6 %. The same is true for other locations where κ was found
to increase with size. While detailed information about aerosol
hygroscopicity can significantly improve the prediction of NCCN, total
aerosol number concentration and aerosol size distribution remain more
important parameters. The seasonal and diurnal patterns of CCN activation
and hygroscopic properties vary among three long-term locations,
highlighting the spatial and temporal variability of potential aerosol–cloud
interactions in various environments. |
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